Cylinder type paper machine



March 5, 1952 R. H. BREYFOGLE ETAL 2,590,288

CYLINDER TYPE PAPER MACHINE Filed April 19, 1947 3 Sheets-Sheet 1 I x m NM R. H. BREYFOGLE ETAL 2,590,288

, CYLINDER TYPE PAPER MACHINE March 25, 1952 3 Sheets-Sheet 3 Filed April 19, 1947 ea 92 4e [Hz Er: far-'5 for IV fiesrx-oas ,eaaser E flaus Patented Mar. 25, 1952 UNITED {STATES PATENT OFFICE Roy H. 'Breyfogle and Robert F. Hollis, Alton, 1 assignors to Alton Box Board ilompany, Alton, 1 11., a corporation Delaware Application April-9, 194.1, -.Seria1 No. 242,708

7 Claims.

This invention relates to a cylinder type paper machine and more particularly to an improved cylinder mold construction and arrangement :for sealing the ends of the cylindermold relativelto the side walls of the vat in which the mold rtates.

In the operation of a typical cylinder type paper machine, the cylinder mold rotates in a stock vat which retains a pond of pulp stock in which the cylinder mold "is partially immersed. As the cylinder mold rotates, the pond liquid passes through the screen, or forming wire, surface of the 'mold'a'nd out of the ends of "the mold into drain boxes carried by the vat walls. .As the liquid passes through {the forming wire surface, it deposits its fibers as a web on this surface. This web is lifted from the cylinder surface by a ,pick-upfelt which :is pressed against the cylinder by a couch roll.

In presently known machines of "this type, no satisfactory arrangement is provided for .supporting the edges of pick-up Tel'ts "which extend beyond the normal face width of "the cylinder mold. Lack of such an arangemen'tis primarily due to the garter-belt type of :seal which is commonly employed to seal on the ends of the cylinder moldfro'm the pond of liquid in the stock vat to prevent this liquid from by-passing the forming wire surface. This Jtype of seal .reqii'ir'es a relatively wide gap or slot between each end of the cylinder mold and its adjacent vat wall to receive avbelt which spans a seal ring attached to the end of the cylindermold and an adjacent seal ring attached to the vat side wall to seal off the ends of the cylinder 'from'the pond. It is found in practice that these slots, one at each end of the cylinder mold, permit the edges of pick-up felts, which are wider than the normal face width of the cylinder, 'to drop into the slots thereby creasing the pick-up felt adjacent its edges and causing wear on boththe -lelt and the cylinder.

Besides preventing the use of a satisfactory arrangement for supporting the "edges of pick-up felts which are wider than the normal lace-width of the cylinder, this gartere'belt typefo'f "sealha's been found to have numerous other disadvantages. Since it employs .airelativelywide belt :in which a portion of the flat belt surface rotates against a fixed ring attached to thevat side wall, there is considerable frictional resis'tancebetween the belt surface :andithe surface of'lthe "vat which'is contactedihy thebelt. This'typ'e 'oioontact also causes considerable wear and tear :on both the 'belt 'andthe seal rings, particularly the fixed seal rings. Foreign matter may become trapped "under the loeltand carried into contact with the annular surfaces of the sealing rings 'therebycaus'ing leakage through the seal and producing undue wear on component parts of the seal. The belt often gets loose on the run and when replacements are to be made it "is necessary to dismantle the seal, at least insofar as taking off the =be1t is concerned, in order to remove the cylinder mold from the vat and the angle type seal rings employed for this type of seal are difficult to replace in the field.

To overcome such disadvantages as these, we have invented a cylinder type paper machine an improved cylinder mold construction for supporting the edges of felts pressed against the cylinder and an improved arrangement for sealing the ends of the cylinder mold relative to the vat side walls, these novel features of our inven'tion being economical to manufacture and resulting in l'ower maintenance costs during op- 'Oin seal arrangement has a self-cleariing action and possesses sufficient tightness for use on cylinder type paper or board-making machines, gravity :dec'lcers, syrup or slurry cleaners, etc. Whereas vinrmachine utilizing the :garterbelt type of seal :there is :a relatively wide gap slot between each :end of the cylinder mold and the wattside iwal'ls, we provide a felt support ring forming an extension :of the normal face width of the cylinder .mold, thereby eliminating any slot at this location except for the necessary small clearance between the ends of theseitelt .sopport rings and the vat side .walls. With our menstruation, new and wider felts can he carried hyith'e icylinderm'old without causing creasing :of the felt edges.

To effect sealing between the ends of the cylinder mold and the wet side walls, we provide a resilient annular seal projecting axially from each and PM the icylinder mold :andlaearing endwise against a wearing ring mounted on each vat .side wall. since the annular seal contacts against the wearing ring throughout a substantially iunbrokenannular area :of contact, the otherwise open end of the cylinder mold is rather completely sealed with the result that aneduction fan can operate more effectively .in producing suction through the interior of the cylinder mold. Suitahlematerialsare :chosen to minimize theini'tial cost of our improved structure to keep maintenance 'costsflow, and "to minimize .the frictional load caused by contact between the annularfseal'tand thewearing ring. Provision is made "for periodically'rlieving compression on segmental portions of the resilient annular seal to maintain said resiliency and to foster the self-cleaning action of the seal arrangement. With our arrangement, the felt support ring and the resilient seal assembly are. readily demountable and replaced in the field and furthermore, in contrast to the garter-belt type of seal, the cylinder mold can be taken from or replaced into the vat without requiring manipulation of the end seals.

It is, therefore. an object of our invention to provide an improved cylinder mold construction and seal assembly for a cylinder type paper machine which is economical to manufacture, easy to maintain, and readily demountable.

It is another object of our invention to provide an improved cylinder mold construction and seal assembly for a cylinder type paper machine the felt support ring and seal assembly, with a resilient seal unit being shown compressed which enables the cylinder mold to be readily removed from or placed into the stock vat without requiring special manipulation of the seal assembly.

It is another object of our invention to pro-'- videa seal assembly .for a cylinder type paper machine in which the assembly has a self-cleaning action and is sufficiently tight to render more effective the action of an eduction fan in producing .suction through the interior of the cylinder mold. fIt is another object of our invention to provide an improved cylinder mold construction for a cylinder type paper machine .in which the cylinder mold can support felts wider than the normal face width of the cylinder without creasing'the edges of said felts.

It is another object of our invention to provide a seal assembly for a cylinder type paper machinein which a resilient annular seal member bears against a cooperating surface provided on a wall of the stock vat. r

It is another object of our invention to provide a seal assembly for a cylinder type paper machine in which a resilient annularseal member bears against a cooperating surface provided on the wall of the, stock .vat, and in which friction between the annularseal member and said cooperating surface is minimized.

It is another object of our invention to pro- .videga seal assembly for a cylinder type paper machine which includes a plurality of resilient seal unitsarranged concentric with each end of the; cylinder moldand. projecting endwise therefIUm-'1'I"I I I :-.Itfis.another. object-of our invention to provide a, seal assembly for a .cylinder type paper ma chine: which includes a plurality of resilient-seal units positioned in a .ring formation ateach end of the cylinder mold, said seal units being ca-i pable, of .being compressed against a cooperating surface provided on a wall of the stock vat.

It :isanother object of our invention to providea seal assembly for a cylinder type paper machine which includes resilient seal units arranged in a ring formation at each end of acylinder mold and compressed against a cooperating surface provided on a wall of a stock vat, and means to maintain the resiliency of said seal units despite such compression.

These and other objects and advantages of our invention will become apparent from. the following .detailed description taken in conjunctionwith the attached drawings in which,

Fig. 1 is an end elevational view of a cylinder type paper machine with an end wall .of the stock vat'beingbroken away in part to expose the cylagainst the main portion of the wear plate ring shown in Fig. 2. ;Fig. 6 is a view similar to that of Fig. 5 in which the resilient seal unit is shown as being relieved of compression by extending into a depression formed in the wear plate ring shown in Fig. 2.

Fig. 7 is a side view similar to that of Fig. 5 and shows an alternate type of resilient seal unit.

Fig. 8 is a frontal view, with a portion being exposed in cross section, showing the side by side arrangement of the resilient seal units.

Fig. 9 is a view similar to that of Fig. 8 showing an alternate type of side by side arrangement.

Referring to the general assembly shown in Fig. 1 of the drawings, a stock vat I0 is shown as being supported upon base rails II and as including side walls I2 and end Walls I3, the latter being provided with outwardly projecting strengthening flanges I4 arranged in grid formation. A cylinder mold, denoted generally by the reference numeral I5, is positioned in the stock vat I0 and supported for rotation in said vatby shaft ends I'B which extend through packing rings I! mounted in the side walls I2 of the stock vat into suitable journal boxes I8 adjacent each side wall. Through suitable connections to a power source, not shown, the cylinder mold I5 is rotated in the stock vat ID. Each side wall of the stock vat includes a drain box I9 for receiving the drainage from the interior of the cylinder mold I5 and outlets 20 for connection with an eduction fan, not shown.

The cylinder mold I5 has a foraminous or screen'surface 2| composed of forming wires 22. Round bars 23. which extend between the end spiders 24 and 2,5 of the cylinder mold, support the forming wires. Each of the end spiders includes a plurality of radial arms 26 which extend from the spider hub to the spider ring 21, the latter having its outer curved surface 46 substantially'flush with the forming wire surface 2 I. As can be observed from Fig. 1 of the drawings, the ends of cylinder, mold I5, as represented by end spiders 24 and 25, are adjacent the vat side walls I2. The space between an end of the cylinder mold and a side wall of the stock vat, for example, the space between end spider 24 and vat wall I2, would, with the garter-belt type of seal, be a slot into which the edges of felts extending beyond the end spiders would drop. This, as we havepreviously mentioned, is a serious disadvam tage of the garter-belt type of seal. We eliminate this disadvantage by providing felt support rings 28 and 29 at each end of the cylinder mold I5. From an inspection of Fig. 1 of the drawings, it can be seen that these felt support rings extend substantially to the vat side walls I2 thereby eliminating the relatively wide slot found in machines utilizing the garter-belt type of seal.

Adjacent each end of the cylinder mold I5, the vat sidewalls I2 are provided with an opensho t. s i eiw e t f and ten ""48 "and bolts 50 "secure the 3| includes the outlet 20 which, as has been pie viously mentioned, can be connected to an educ' tion fan. The removable wall pbrti'o'n 3| also in cludes a portion 32 which extends above the up= per edge 33 of the vat side wall 12.

This last mentioned portion 32 has attached thereto a ring segment 34 and a plurality of other ring segments 35 are attachedto the-inner wall surface 33 of the vat side wall |2. While any suitable means of attachment might be used; we illustrate countersunk metal screws 31 as secur ing the radially outward portions of segments 35 to the wall surface 36. The segments 35 are pbsi tioned end to end, as shown in Figure 2-, and terminate in spaced offset end segments "35a receiving the segment 34 therebetween to completea ring 38 which we denote as a wear plate ring.

The end segments 3511 are inwardly "offset with respect to the ends 39 and 40 'of'the adjacent ring segments 35 and are secured to the vat sidewall |2 by screws 4| which are radially inward of the screws 31. The segments 35a have vertical ends 42 closely adjacent or abutting the vertical edges of the segment 34. Also, the width, or radial depth, of the faces 43 of ring "segments 34-and 35a is greater than the corresponding 'width of I the face 44 of each of the other ring segments 35. With the width of faces '43 of segments 35 and 35a being greater than the width of the face of each of the other ring segments 35, and since the abutting ends '42 abut along vertical lines, it is possible to vertically adjust the position "of the wall part 3| and hence vary the position "of ring segment 34 without destroying the continuity .of 'theuring formed by segments 34, 35, and 35a. This provides flexibility in operation since even if a cylinder mold is'substituted which is not centered exactly as the preceding mold, the "coirtinuity of the wear plate ring 38 on'the vat 'side wall need not be interrupted because aportion of this ring, i. e;, segment 34, is adjustable to compensate for the difference in centering Of course, it is realized that variations between 'inolds should not be so great as to be beyond the "adjustment possibilities of segment -34. Further, the seals to-r'ide onthe wear plate'will be in ardiy of the screws 31 and 'outwa'rdly 'o'f *the'screw's '41 so that the heads of the screws win-riot "tear the seals. 7

Details of "the felt support ring construction and the seal assembly are best Figs. '5 and 6 bf the drawings. Afs inest-rated "there, the felt support ring 28 mense a felt support surface 45 which is s auynush with the outer surface 46 fo'f end spider 24 and with the forming wire s'urface 21. ifrererabiy-the surface 45 slopes downwardly toward the edge 45?: of the felt support ring asis'show'n in and '6. The support surface 45 is pre rablya Lard. stainless metal cover sprayed on the periphery of thering28. W v The felt support "ring 38 als'o i'nc d "41 which -is abutted against the 's'pder 2 4. A shoulder inte'rlb'dlr'fi's hence a it obtained from "6 the ens race 43 of spider 24. As can be observed from Figs. 5 and '6, the edge 5| of a pickup felt '52 iends over onto and. is supported by the felt support surface '45; Positioned concentric with the circular flang 5315f the felt support ring 28 is a second ring 54 which has its outer circumference 55 abl'lttd against the inner circumference 56 of flange 53. The ring 54 is bolted to the flange 4'! of felt Suppb'rt ring 28 by means such as bolts 51", and "sleeves 58 are provided intermediate the ring 54 "and flange 41 to maintain these parts spaced from each other. By selecting different lengths or sleeves 58, it is obvious that different spacings could be provided. Ring 54 is provided with a downwardly extending lip 59 which grips a flange 6'0 of a resilient seal unit denoted generally by the numeral iii and preferably composed er rubher or a synthetic rubber-like material; e'p positely extending flange E2 of the "resilient seal unit BI is gripped by a retaining ring 63 which is suitably secured to the ring 54 by means such -as countersunk screws 64. A T-groove lock is thereby provided. If necessary, shims can be used to secure a tight grip on the flanges and 52.

The oppositely extending flanges 60 and '62 are parts of a base portion 65 of the resilient seal unit 6|. This base portiont5 is integrally connected with a head portion 66 by a reduced neck portion 61. The head portion 66, as viewed from the side, is of bulbular shape and has an aperture 68 extending therethrough. The head portion '66 is also provided with a hardened end, which can be called a tip or nose, and which is indicated at 69. This tip or nose can be a vulcanized insert of hardened rubber or the like. In Fig. 5 of the drawings, the resilient seal unit 6| is'shown compressed endwise against face surface 44 "of a segment 35 of the wear plate ring 38 shown in Fig. 2. The hardened nose 69 is in contact with face surface 44. Since the head portion 66 of seal unit 6| is apertured, it tends to bulge uniformly to either side of the hardened nose 69 instead of buckling off-center.

These resilient seal units 6| are positioned in sealed-together side by side relation as shown in Fig. 3 of the drawings and form a resilient annular seal concentric with the felt support rings, such as felt support ring 28, and also concentric with the end spiders such as end spider 24. The circumferential dimension of each seal unit 6| is only a small fraction of the radius of the resilient annular ring formed by the contiguousunits. In this manner they substantially completely seal off the small space that exists between the ends of the felt support rings and the vat side walls. Referring to Fig. 5, such a space is shown as existing between the edge 45a of felt support surface '45 and the face 44 of wear plate ring segment '35.

-If the resilient seal units were maintainedcdmp'ressedat-all times, they would soon become se' and lose their resiliency thereby impairing the efficiency of the seal. To prevent this from occurrin Weprovide a means for relieving-the com-- pression on these seal units. This means is a depression 1| which-is provided in the face surface 43 of wear plate'ring segment 34. Referring to Figs. '2, 4 and 6, this depression is shown "as including beveled walls 12 and 13 and the flat 'wall 14 therebetween. The depression H extends "the width of theface 43 of wear plate ring seg- -me'nt 34 so as to be effective despite variation in the positioning of this ring segment with respect to i'tsjadjacent wear plate ring segments 35, p

With this arrangement, as thecylinder rotates,

- walls 12 and 13 of the depression H. Of course,

the wall surface 14 of this depression is not sunk far enough inward to provide a large gap between the wall and the ends of the seal units 6!, but is sunk far enough inward to relieve at least some of the compression load of these units. In addition to relieving compression on the resilient seal units 6|, the depression II also provides an outlet for pieces of string and other debris that might be caught by the seal and which would otherwise have no means of escape. Hence the seal assembly is self-cleaning in action.

An alternate form of resilient seal unit is shown in Fig. 7 of the drawings. This seal unit, denoted generally by the reference numeral 15, includes a base portion 16 having oppositely extending flanges TI and 18 which are retained by a ring 19 and an auxiliary ring 80 in a manner similar to that described above for the resilient seal units '6 I. The seal unit 75 also includes a head portion 8! which has a plurality of apertures 82 there- -through. This head portion 8| has its end surface arranged as two humps 83 and 84 which are separated by a valley 85. The head portion BI is integrally connected with the base portion 16 by a reduced neck portion 86. The resilient seal units 15 are positioned side by side in the manner illustrated for resilient seal units 6| in Fig. 3 of the drawings. Being so positioned, and since the individual units 15 are identical, the humps 83 and 84 form concentric rings so that, when the seal units are abutted against a face surface such as face surface 87 indicated in Fig. '7 of the drawings, they will contact this face surface along two concentric annular areas of contact. Hence, with the type of resilient seal unit shown in Fig. 7 of the drawings, a double contacting surface is provided. A means for relieving compression similar to that described for resilient seal units 6| can be provided for the resilient seal units 15.

Since the resilient seal units (it are positioned side by side, it is desirable that their head portions 66 be restrained against sideways movement with respect to each other in order that a substantially uniform annular seal will be provided. In other words, individual seal units 6| should not move radially of the cylinder with respect to each other so as to become offset from each other. In one side by side arrangement 11- lustrated in Fig. 8 of the drawings, the sides of the head portions are partially interlocked by dove-tailing the head portions together. The sides 88 and 89, and 90 and SI, of the adjacent head portions 66 of the individual seal units Bl shown in Fig. 8 are, for each head portion, oppositely inclined. However, in positioning the seal units side by side, sides having the same inclination such as sides 88 and 9!, 89 and 90, are placed against each other, thereby producing a dove-tail arrangement as is shown in Fig. 8.

In the interlocking arrangement disclosed in Fig. 9 of the drawings, instead of utilizing the dove-tail arrangement, the individual head portions 66 of the resilient seal unit 61 are provided with a generally conical projection centered at one side and a generally conical recess centered at the other side. This enables the projection of one unit to seat in the recess of its adjacent unit to interlock the head portions against movement with respect to each other in a direction radially of the cylinder. For example, in Fig. 9, a head portion 66 is shown as having a projection 92 seated in a recess 93 of the adjacent head portion 66 of the adjacent seal unit and this adjacent head portion likewise has a side projection 95. For this type of interlock, it is desirable that the rotation of the cylinder mold be such that the seal units travel in the direction of their side projections, i. e., to the left as viewed in Fig. 9.

The individual seal units, such as seal units BI and 15 should be formed of a material which possesses sufiicient resiliency to allow for compression of these units against the wear plate ring 38 and which, nevertheless, does not cause an excessive friction load despite the pressing of the seal units against the wear plate ring. We have found it satisfactory to provide molded rubber seal units, a buna compound synthetic rubber having been found to be particularly satisfactory both from a standpoint of resiliency and minimizing friction with the wear plate ring. For the type of seal unit illustrated in Figs. 5 and 6 of the drawings, that is, seal units 6|, we find that friction between the seal units and the wear plate ring can be further reduced by providing a hard rubber nose, indicated at 69 in Figs. 5 and 6, on each of the seal units and this nose is the portion of the seal unit which contacts against the wear plate ring. In forming the seal units, the

hard rubber nose is preferably vulcanized to the rest of the seal unit so that there is little danger of the nose becoming loose from the body of the seal unit. Instead of utilizing a hard rubber nose, a suitable metal or plastic nose could be used. Also, instead of using the rounded type of nose indicated at 69, other suitable nose shapes could be employed such as a ribbed or fluted construction. We have disclosed an alternate form in Fig. 7.

Since the wear plate ring 38 has travelling against it a plurality of seal units which are wetted by the pond of pulp stock, and since a portion of the wear plate ring actually extends below the surface of this pond, the wear plate ring should be formed of a material which will maintain a smooth surface despite the presence of this liquid. Accordingly, we prefer to use Monel metal for the wear plate ring. Parts such as the bolts 50 and 51 and screws 31 and 64 are also preferably formed of Monel metal in order to prevent their sticking in place due to rusting which, of course, would hamper replacement work and increase maintenance costs. While we mention these specific parts of our structure and identify materials which We find suitable for these parts, it should be quite evident that parts not specifically mentioned by us will be also formed of a material suitable for the purpose which the particular part is intended to meet.

From the foregoing description, it can be seen that the cylinder type paper machine described by us overcomes many of the disadvantages now present in existing machines of this type known to the prior art. In our machine it is relatively simple to remove the cylinder mold from the stock vat. Specifically, the removable wall part 3| can be taken from above the packing ring I1, and, when this wall part is so removed, the segment 34 of wear plate ring 38 is also moved to provide a clear path upward from the bearing ring. Hence, the shaft ends I6 can be readily lifted 9 clear of the stock vat. Note further that-the resilient seal units, such as units 61, neednot: be dismantled from the ends of the cylinder mold since the seal units will simply slide against; the wear plate ring 38 as the cylinder is lifted out of the stock vat. As has been previously mentioned, this is quite an advantage over machines employing the garter-belt type of seal where the seal itself, at least the belt portion thereof, has to be manipulated in order to permit removal of the cylinder mold from the stock vat.

The type of seal which we provide enables us to utilize a felt support ring having a felt support surface substantially flush with the forming wire surface of the cylinder mold thereby eliminating any relatively wide slot between the ends of the cylinder mold and the side walls of the stock vat. Hence, pick-up felts which have edges extending beyond the normal face width of the cylinder mold are not creased as has heretofore occurred. The advantages of having a seal arrangement which'is self-cleaning in action, i. e., will tend to get rid of objects such as string, sticks, etc., caught by the seal, and which substantially closes off the entire end of the cylinder mold, also contributes greatly to the efiiciency of the apparatus which we disclose. It is apparent that the components of the seal assembly and the felt support ring construction are readily demountable thereby facilitating maintenance in the field and keeping maintenance costs low.

While we have described particular embodiments of our invention, we do not intend to be restricted solely to the exact constructions disclosed, but do intend to cover all modifications thereof which would be readily apparent to one skilled in the art and which come within the spirit and scope of our invention as set forth in the appended claims.

We claim as our invention:

1. In a cylinder type paper machine having a stock vat including oppositely disposed walls, and a cylinder rotatable in said vat with the ends of said cylinder being adjacent opposite walls of said vat, apparatus for sealing ofi the space between an end of said cylinder and a wall of said vat comprising an annular rubber-like seal compressed between the vat wall and the cylinder end, said seal being attached to and rotatable with said cylinder, said vat wall having a part defining a course for said seal, said course being non-uniformly spaced from said cylinder end.

2. In a cylinder type paper machine having a stock vat including. oppositely disposed walls, and a cylinder rotatable in said vat with the ends of said cylinder being adjacent opposite walls of said vat, means for sealing the ends of said cylinder to the walls of said vat comprising a ring formed by a plurality of adjacent rubber-like resilient seal units arranged concentric with each end of said cylinder, said seal units being attached to said cylinder and projecting endwise therefrom, a wear plate ring mounted on each of said vat walls in extension of the seal units at each end of said cylinder, said seal units being abutted endwise against said wear plate rings, and said wear plates having a localized shallow depression whereat the axal space bridged by said sealing units is greater than elsewhere.

3. A paper making machine comprising a stock vat for receiving a pond of pulp stock, said vat having side and end walls, a foraminous cylinder,

' means supporting said cylinder for rotation in the vat with the ends of said cylinder adjacent the vat side walls, a felt support ring attached to each end of said-cylinder, said felt support ring having a cylindrical surface in axial extension of the surface of said foraminous cylinder, a ring formed of a plurality of resilient seal units at each end of said cylinder, said ring of seal units being arranged concentric with the cylinder ends and projecting beyond the felt support ring, a wear plate ring attached to each vat side wall, each of said wear-plate-rings being positioned in extension of the seal units projecting from theends ofsaid cylinder, and said seal units being abutted endwise against said wear plate rings throughout an annular area of contact at each of said wear plate rings to seal the ends of the cylinder from the pond of pulp stock within the vat.

4. A paper making machine comprising a stock vat for receiving a pond of pulp stock, said vat having side and end walls, a foraminous cylinder, means supporting said cylinder for rotation in said vat with the ends of said cylinder adjacent the vat side walls, a felt support ring attached to each end of said cylinder, said felt support ring having a cylindrical surface in axial extension of the surface of said foraminous cylinder, a plurality of resilient seal units at each end of said cylinder, said seal units being arranged concentric with the cyilnder ends and projecting beyond the felt support ring, a wear plate ring attached to each vat side wall, each of said rings being positioned in extension of the seal units projecting from the ends of said cylinder and defining a course for said seal units, said seal units being compressed between a wear plate ring and the end of the cylinder adjacent thereto to seal the ends of the cylinder from the pond of pulp stock within the vat, and said wear plate ring having a depression in the course of said seal units to periodically relieve the compression on each of said seal units as the cylinder rotates.

5. In a cylinder type paper machine in which felt of a width greater than the cylinder mold is employed, a cylinder mold having a forming wire surface and having attached, at each end of said cylinder mold, a ring having a flange secured to the corresponding end surface of the cylinder mold and also having a felt support surface substantially flush with and in axial extension of the forming wire surface of said cylinder mold, and a seal carried by said ring radially inward of said felt support surface.

6. In a cylinder type paper machine, a cylinder mold having a forming wire surface. a felt support ring attached to each end of said cylinder mold, each of said felt support rings having a felt support surface substantially flush with the forming wire surface of said cylinder mold, a second ring positioned adjacent each end of the cylinder mold, each of said second rings being attached to its corresponding felt support ring, and a plurality of resilient seal members supported by each of said second rings and extending axially beyond the ends of their corresponding felt support rings.

7. In a cylinder type paper machine having a stock vat having parallel side walls for receiving a pond of pulp stock and a cylinder rotatable in said vat between said side walls, means for internally evacuating said cylinder, and means for sealing the ends of said cylinder from said pond comprising a multiplicity of separate rubber-like seal units arranged in circumferential contiguity to form a ring, the circumferential dimension of each seal unit being a small fraction of the radius of said ring, said ring being compressed axially between the end of said cylinder and the adjacent side wall of the vat.

' ROY H. BREYFOGLE. ROBERT F. HOLLIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Beaumont Jan. 4, 1916 15 Number I Number 12 Name Date Bidwell July 31, 1923 Madsen May 17, 1932 Michell Dec. 20, 1932 Schanz Apr. 23, 1935 Leeson June 15, 1943 Lowe et a1 Jan. 18, 1944 Goodwillie et a1. Mar. 19, 1946 FOREIGN PATENTS Country Date France Mar. 9, 1939 :Germany Feb. 3, 1932 Germany Feb. 7, 1938 

